The present invention relates to a cutter head in a machine tool that can be favorably applied to a shaving machine in order to facilitate a cutter replacement operation.
One example of the heretofore known cutter heads in a shaving machine is schematically illustrated in cross-section in FIG. 6. In this figure, a cutter head main body 101 is mounted to a head carrier 102 so as to be rotatable by about .+-.20 degrees within a horizontal plane about a vertical axis so that a cutter can be engaged with a workpiece, and a cutter spindle 103 is rotatably supported by the cutter head 101 via bearings 104, 105 and 106. To this cutter spindle 103 is fixedly secured a drive gear 107, and the cutter spindle 103 is rotatably driven by a main shaft motor, not shown, by the intermediary of this drive gear 107. A shaving cutter 108 is fitted around a tip end portion of this cutter spindle 103, sandwiched between cutter collars 109, and fixedly mounted by fastening a nut 110. On the other hand, in the proximity of the tip end of the cutter spindle 103, a cutter support 111 is detachably fixed to the cutter head main body 101 by means of bolts (not shown), and the tip end of the cutter spindle 103 is supported by being fitted in a bore 115 drilled in a support shaft 114 that is rotatably supported within the cutter support 111 via bearings 112 and 113.
In such a heretofore known cutter head, upon mounting or dismounting a shaving cutter 108, each time the cutter support 111 is dismounted by loosening the bolts, the nut 110 is removed, and thereafter the shaving cutter 108 is fitted around or extracted from the cutter spindle 103.
The above-described prior art cutter head involves the following problems:
(1) Upon replacement of a cutter, since the cutter support 111 must be dismounted each time, the cutter replacement operation becomes complex.
(2) Since the cutter spindle 103 extends nearly in the left and right directions as viewed by an operator under the condition where the operator faces the shaving machine, the operator must fit or extract the shaving cutter 108 to or from the cutter spindle 103 in the lateral direction, and such operation is awkward. In other words, this cutter replacement operation forces the operator to take an unnatural attitude, and may possibly cause an injury such as a back injury of the operator.
(3) Since the gap clearance at the fitting portion between the cutter spindle 103 and the shaving cutter 108 is as small as several microns because of the demand for precision in a shaving operation, in association with the above-mentioned awkwardness, the operation of fitting or extracting the shaving cutter 108 to or from the cutter spindle 103 requires a high level of skill.
(4) As the cutter replacement operation is complex and needs a high degree of technique, it is impossible to automate the cutter replacement operation.